Solution for “Package ‘Microsoft SQL Management Studio Package’ failed to load”

I had an odd issue where SQL Server Management Studio (SSMS) 2008 R2 would start up, display the following error message, then exit:

Package ‘Microsoft SQL Management Studio Package’ failed to load

Using SysInternals Process Monitor tool to monitor SSMS.exe it seemed that it was looking for the following registry key but not finding it:

HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server\100\Tools

By renaming a parent key (rather than delete it – just in case it didn’t fix the issue) solved the issue for me. The key I renamed was:

HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server

Running SSMS again recreated the \100\Tools sub keys and all was well again. I hope it works for you too.